Comparative Study On The Distribution Of Macrophage In Normal Skin, Keloid And Hyperplastic Scar At Different Growth Stages

Objective:At present the formation mechanism of pathological scar has not yet been determined, and also lack of effective treatment methods of pathological scar. But more and more research suggests that macrophage plays an important role during wound healing process. Pathologic scarring is related with amount and function of the macrophage. This experiment is trying to compare the distribution of macrophage in normal skin, keloid and hyperplastic scar at different growth stages with immunohistochemical method.Method:We collected 17 clinical pathologic scar specimens after surgery, and then divided them into four groups: keloid for group A, hypertrophic scar for group B(time of hypertrophy is less than 6 months ), hypertrophic scar for group C (time of hypertrophy is between 6 and 12 months), maturity scar for group D (time of hypertrophy is more than 8 years). Another 3 samples of the normal skin are used as control group, which we called group E. The specimens were fixed by 10% neutral formalin for 12 hours and then dehydrated with the gradient alcohol. Embedding the specimens with wax and then sliced them into section. Haematoxylin-eosin (HE) staining and immunohistochemistry staining with mouse anti-human CD68 monoclonal antibody were performed. In immunohistochemistry staining the positive signal of macrophage was brown granules. The method of the macrophage image analysis: the positive particles of macrophage of each group was observed and then count under the 400 times microscope, the average number of five visions which were taken from each section were compared (by the same people under the same condition).Result: 1. The morphology of HE staining under the light microscope:①The stratum lucidum and the stratum corneum of normal skin are thick; the dermal papilla is obviously; the fibroblast is seen in reticular layer, which has small nuclear and less cytoplasm.②The epidermis of keloid is atrophic, the cyton of stratum basale and stratum spinosum is large, and the number of layer increased; in stratum granulosum, stratum lucidum and stratum corneum we could only see a thin layer of eosinophilic staining which could not been distinguished; the dermal papilla could be seen, but the amount is very small, and the dermal papilla is low and flat; reticular layer is thick, dense, and the collagen could be seen which stained dark, disordered, and hyaline degeneration, blood vessels, lymphatic vessels and atretic capillary could be seen. There are lots of fibroblast in those two layers.③Compared with normal skin the number of layer of stratum lucidum and the stratum corneum of hypertrophic scar are thicker, also the connection among the cell is looser, stratum lucidum and stratum corneumn are thinner, the dermal papilla of dermal papilla is lower, and has a small amount. Reticular layer is thick, dense; blood vessels, lymphatic vessels and angiotelectasia could be seen. There are lots of fibroblasts in those two layers.④In maturity scar, short columnar cell of stratum basale in epidermis connect with dermis. Adherent to the basement membrane, the number of the layer is less than in hypertrophic scar; and the connection among the cells is looser than that in normal skin. The cells are spindle in stratum granulosum, and more flate than that in normal skin; also the stratum lucidum and the stratum corneum are thinner. The dermal papilla is looser; the reticular layer is thinner and denser than that in hypertrophic scar and keloid, dark stained collagen and atretic capillary could be seen. 2. The analysis of the image of immunohistochemical staining: The number of macrophage between pathologic scar and normal skin has a statistical significance (P<0.01). The number of macrophage in keloid is bigger than in hypertrophic scar (time of hypertrophy is less than 6 months), with a statistical significance (P<0.01). The number of macrophage in keloid is bigger than in maturity scar, with a statistical significance (P<0.05). The number of macrophage in hypertrophic scar is bigger than in maturity scar, with a statistical significance (P<0.01). The number of macrophage has no statistical significance (P>0.05) between keloid and hypertrophic scar (time of hypertrophy is between 6 and 12 months). The number of macrophage has no statistical significance (P>0.05) in hypertrophic scar between different stage of hypertrophy.Conclusion:Compared with normal skin, the distribution and amount of macrophage in keloid and hyperplastic scar at different growth stages are different, the macrophage may plays an important role during wound healing process.